1. Field
Exemplary embodiments of the present invention relate to a semiconductor design technology and more particularly, to an image sensing device.
2. Description of the Related Art
Recently, consumer demand for image sensing devices has been increasing in various fields such as mobile cameras, digital cameras, monitoring cameras, and endoscopes for medical use.
Generally, an image sensing device, also referred to as an image sensor, captures images using the photosensitive properties of semiconductors. Image sensing devices may be classified into charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. CMOS image sensors are more widely used and allow direct implementation of all needed analog and digital control circuits on a single integrated circuit (IC).
Although an image sensing device may generally adopt a correlated-double sampling (CDS) scheme for correcting fixed pattern noise occurring due to characteristics of a pixel, it is generally more difficult to correct process variations of a parasitic capacitor included in the pixel. Further, since an image sensing device may adopt a source follower structure between a pixel and a read-out path, conversion gains of the pixel may not be compensated or controlled.